The drain connection between a household appliance and a sanitary system often includes a standpipe. A hose or other flexible member is connected between the appliance and the standpipe. In other sanitary systems, the drain outlet of the appliance may be connected to a flexible hose which discharges into a laundry, or wash, tub. Should the outlet end of a drain hose become submerged below the drain water level in either a standpipe or tub, the hose is capable of siphoning the grey water back into the appliance, unless a siphon break has been provided between the appliance and the source of the grey water being so siphoned.
As such, drain connections have required the inclusion of a siphon break in the drain line at a location upstream with respect to the grey water which might be siphoned back into the appliance. One suitable solution to this problem was incorporated in the "Universal Standpipe Adaptor" that is the subject of U.S. patent application, Ser. No. 07/621,046 filed on Nov. 29, 1990, in the name of Anthony Dlouhy and assigned to the assignee of this application. This device provides a siphon break structure in conjunction with a universal adapter which can be connected to a sanitary system standpipe.
Other prior art approaches for providing a siphon break have been unduly complex and expensive to install. While these complex prior art devices may be effective, they will not accomodate all sanitary systems, and they do not provide a positive valving mechanism to prevent the leakage of liquid through the structural arrangement which provides the siphon break.